tsiry-sandratraina.com
A modern Music Player Daemon based on Rockbox open source high quality audio player
libadwaita
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rockbox
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Add a small 32-byte write buffer to fdprintf.
Avoids a call to write() for every output character. It doesn't
need to be very large to have a great effect on speed and realize
most of the potential.
Change-Id: I11820c1968ed7b20aa00e106a022c1b864b03d21
+23
-4
firmware/common/fdprintf.c
+23
-4
firmware/common/fdprintf.c
···
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*
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****************************************************************************/
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#include <limits.h>
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#include "system.h"
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#include "file.h"
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#include "vuprintf.h"
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#define FPR_WRBUF_CKSZ 32 /* write buffer chunk size */
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struct for_fprintf {
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int fd; /* where to store it */
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int rem; /* amount remaining */
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int idx; /* index of next buffer write */
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unsigned char wrbuf[FPR_WRBUF_CKSZ]; /* write buffer */
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};
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static int fpr_buffer_flush(struct for_fprintf *fpr)
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{
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/* set idx to actual but negative unflushed count to signal error */
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ssize_t done = write(fpr->fd, fpr->wrbuf, fpr->idx);
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fpr->idx = MAX(done, 0) - fpr->idx;
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return fpr->idx;
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}
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static int fprfunc(void *pr, int letter)
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{
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struct for_fprintf *fpr = (struct for_fprintf *)pr;
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/* TODO: add a small buffer to reduce write() calls */
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if (write(fpr->fd, &(char){ letter }, 1) > 0) {
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return --fpr->rem;
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if (fpr->idx >= FPR_WRBUF_CKSZ && fpr_buffer_flush(fpr)) {
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return -1; /* don't count this one */
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}
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return -1;
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fpr->wrbuf[fpr->idx++] = letter;
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return --fpr->rem;
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}
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int fdprintf(int fd, const char *fmt, ...)
···
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fpr.fd = fd;
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fpr.rem = INT_MAX;
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fpr.idx = 0;
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va_start(ap, fmt);
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bytes = vuprintf(fprfunc, &fpr, fmt, ap);
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va_end(ap);
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/* flush any tail bytes */
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if (fpr.idx < 0 || fpr_buffer_flush(&fpr)) {
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bytes += fpr.idx; /* adjust for unflushed bytes */
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}
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return bytes;
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}